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Many species show changes in distribution and phenotypic trait variation in response to climatic warming. Evidence of genetically based trait responses to climate change is, however, less common. Here, we detected evolutionary variation in the landscape-scale distribution of a genetically based chemical polymorphism in Mediterranean wild thyme (Thymus vulgaris) in association with modified extreme winter freezing events. By comparing current data on morph distribution with that observed in the early 1970s, we detected a significant increase in the proportion of morphs that are sensitive to winter freezing. This increase in frequency was observed in 17 of the 24 populations in which, since the 1970s, annual extreme winter freezing temperatures have risen above the thresholds that cause mortality of freezing-sensitive morphs. Our results provide an original example of rapid ongoing evolutionary change associated with relaxed selection (less extreme freezing events) on a local landscape scale. In species whose distribution and genetic variability are shaped by strong selection gradients, there may be little time lag associated with their ecological and evolutionary response to longterm environmental change.

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Right whales () were extirpated from the eastern North Atlantic by commercial whaling. Grey whales () disappeared from the entire North Atlantic in still-mysterious circumstances. Here, we test the hypotheses that both species previously occurred in the Mediterranean Sea, an area not currently considered part of their historical range. We used ancient DNA barcoding and collagen fingerprinting methods to taxonomically identify a rare set of 10 presumed whale bones from Roman and pre-Roman archaeological sites in the Strait of Gibraltar region, plus an additional bone from the Asturian coast. We identified three right whales, and three grey whales, demonstrating that the ranges of both of these species historically encompassed the Gibraltar region, probably including the Mediterranean Sea as calving grounds. Our results significantly extend the known range of the Atlantic grey whale, and suggest that 2000 years ago, right and grey whales were common when compared with other whale species. The disappearance of right and grey whales from the Mediterranean region is likely to have been accompanied by broader ecosystem impacts, including the disappearance of their predators (killer whales) and a reduction in marine primary productivity. The evidence that these two coastal and highly accessible species were present along the shores of the Roman Empire raises the hypothesis that they may have formed the basis of a forgotten whaling industry.